Device for controlling a blocking mechanism in an electric switch and switch cell comprising said device

ABSTRACT

A device is for controlling the movement of a blocking mechanism in an electric switch which is displaceably arranged in a switch cell. The device includes a push element and an oblique surface, whereby the oblique surface extends in the fitting position of the device in the direction of the travel of the switch and the push element can be maintained in a displaceable manner dependent on the position of a door of the switch cell in the switch cell. The push element co-operates with the oblique surface, acting on the blocking mechanism in such a way that the blocking mechanism is located in a release position when the door is closed and in a blocking position when the door is open. The device can be constructed in a simple manner by virtue of the fact that the oblique surface is inclined in a perpendicular position with respect to the direction of travel of the switch and the displacement path of the push element extends in a transversal manner with respect to the direction of travel.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/DE03/00620 which has an Internationalfiling date of Feb. 20, 2003, which designated the United States ofAmerica and which claims priority on German Patent Application number DE202 02 927.1 filed Feb. 21, 2002, the entire contents of which arehereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention generally lies in the field of electric switches, such asthose arranged in such a way that they can be made to travel in aswitchgear cell provided with a door. Further, it generally lies in thefield of electric switches to be used for structurally designing adevice for controlling a blocking mechanism of the switch in dependenceon the position of the door of the switching cell. The device may have apush element and an oblique surface, with the oblique surface extendingin the direction of the travelling path of the switch when the device isin the installed position, and with the push element being helddisplaceably in the switchgear cell in dependence on the position of thedoor of the switchgear cell. Further, the push element may co-operatewith the oblique surface, acting on the blocking mechanism in such a waythat the blocking mechanism is in a release position when the door isclosed and in a blocking position when the door is open.

BACKGROUND OF THE INVENTION

A device for an electric switch formed as a low-voltage circuit-breakeris known from German Patent Specification 195 03 624 C1. In the case ofthis known device, one end of a push element formed as a push rod issupported under spring force on the door by way of a pressure piecefastened to the door of the switchgear cell. In this case, the push rodis arranged in a guiding tube, which is provided with a slit front part.

The pressure piece engages in this slit front part. When the door isclosed, the other end of the push rod rests on the lower end of theoblique surface, inclined in the direction of the travelling path of theswitch, in such a way that it assumes a relatively lowered position withrespect to a sensing angle of the blocking mechanism and the blockingmechanism is consequently in a release position.

In this release position, the travelling mechanism of the switch isreleased for actuation. During opening of the door, the pressure pieceleaves the slit front part of the guiding tube. The push rod followsthis movement under the influence of the spring force until the otherend of the push rod reaches the upper end of the oblique surface, andconsequently achieves a relatively raised position. In this case, thesensing angle is pivoted, and the blocking mechanism is therebytransferred into its blocking position. In this blocking position, thetravelling mechanism of the switch is blocked to prevent actuation.

SUMMARY OF THE INVENTION

An embodiment of the invention includes an object of structurallydesigning a device for controlling the blocking mechanism in such a waythat it is more simple.

According to an embodiment of the invention, an object may be achievedby the oblique surface being inclined transversely in relation to thedirection of the travelling path of the switch and by the path ofmovement of the push element extending obliquely in relation to thedirection of the travelling path.

In such a configuration of a novel device of one embodiment—in which acomponent of the path of movement of the push element runs transversely,i.e. at right angles, in relation to the direction of the travellingpath of the switch—the actuating element can be acted on directly by thepush element, by way of a wedge action on the oblique surface, withoutadditional elements that transfer the movement of the push element ontothe blocking mechanism.

A preferred embodiment of a device provides that the oblique surface isformed on the push element. A device formed in this way can be used forswitches with differently arranged blocking mechanisms, can be producedeasily—for example in the form of a sheet-metal part—and can beretrofitted without major modifications of the switchgear cell or of thepush-in frame arranged in the switchgear cell. In particular, noadditional oblique surfaces have to be provided in the switchgear cellor in the push-in frame of the switch.

A device is preferably provided in switchgear cells in which an electricswitch is arranged such that it can travel and has the blockingmechanism to be controlled for blocking a travelling mechanism of theswitch.

A device formed according to an embodiment of the invention and aswitchgear cell provided with such a device are represented in FIGS. 1to 6.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and details of the invention will becomeevident from the description of illustrated exemplary embodiments givenhereinbelow and the accompanying drawings, which are given by way ofillustration only and thus are not limitative of the present invention,wherein:

FIG. 1 shows a front view of a switching point with a push-in frame,arranged in which is a low-voltage circuit-breaker, which has a recessfor a crank handle of a travelling mechanism,

FIG. 2 shows the travelling mechanism of the low-voltage circuit-breakeraccording to FIG. 1 as a subassembly,

FIG. 3 shows the travelling mechanism according to FIG. 2, but without ahousing and without the recess for the crank handle, a travelling shaftof the travelling mechanism being located in the release position of theassociated circuit-breaker,

FIG. 4 shows a representation corresponding to FIG. 3 of major parts ofthe travelling mechanism, but in the operating position of theassociated circuit-breaker and

FIGS. 5 and 6 show two further representations of the travellingmechanism with a blocking mechanism and with a device for controllingthe blocking mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to FIG. 1, a push-in frame 101 is arranged in a switchgearcell 100 of a switchgear cabinet or a switching station, a low-voltagecircuit-breaker 102 being arranged in such a way that it can be made totravel in a known way in the push-in frame 101. The low-voltagecircuit-breaker 102 withdrawn in the push-in frame 101 (cf. also FIG. 6)has a housing 103 (cf. also FIG. 6) for receiving a switching polesubassembly and a control panel 104, which is fixed to the front side ofthe housing 103, forms the front side of the switch and by which anoperating mechanism and further parts of the switch are covered.

Arranged on the control panel 104 are an overcurrent trip 105, operatingand indicating elements 106 to 110, a hand-wound mechanism lever 111 fortensioning a spring store of the operating mechanism. A crank handle 5is also included, which can be lowered into a recess 14 for actuating adrive shaft 3 (cf. FIGS. 3 and 4) of a travelling mechanism 1 (cf. FIGS.2 to 5).

According to FIG. 2, the travelling mechanism 1 has a housing 2, whichmay expediently be made up of two shell-like halves, between which gearparts and further components are arranged. A turning movement exertedvia the crank handle 5 is converted by the drive shaft 3 (cf. FIGS. 3 to4) into a rotation of a travelling shaft 37 (FIGS. 3 and 4). Arranged onthe drive shaft 3 for this purpose is a worm 36 (cf. FIGS. 3 and 4),which is in engagement with a gear wheel 4.

The longitudinal axes of the drive shaft 3 and of the travelling shaft37 are at right angles to one another. The travelling shaft 37 is notfixedly connected to the travelling mechanism 1, but is displaceable ina profile opening 38 of the gear wheel 4 which is adapted to the profileof the travelling shaft 37. In this way, the travelling mechanism 1 canbe used for circuit-breakers of different sizes and is not tied to aspecific position along the travelling shaft 37.

Attached to the ends of the travelling shaft 37 in a known way aretravelling cranks 39 (cf. FIGS. 3 and 4), which interact with fixedparts somewhat in the way that is schematically shown for example in DE44 20 580 C1 or DE 44 20 581 C1 (FIG. 1 in each case). Also notrepresented is the fastening of the travelling mechanism 1 to acircuit-breaker, since a person skilled in the art is familiar withthis.

As already mentioned, serving for turning the drive shaft 3 mounted inthe housing 2 is a crank handle 5, which, as a difference from otherknown travelling mechanisms (cf. the cited DE 44 20 580 C1 and DE 44 20581 C1), cannot be removed from the drive shaft 3 but is a componentpart of the travelling mechanism 1. The crank handle 5 has a hollowshank 6, which engages around a hexagonal shank 35 of the drive shaft 3(FIGS. 3 and 4) and is displaceable on the drive shaft 1 along thedirection of an arrow 19. Obviously, the drive shaft 3 and the shank 6may also have other profiles, in order to produce a rotationally lockedcoupling which permits a longitudinal displacement.

The shank 6 bears a guiding pin 11, which engages in a guiding groove 13provided on the housing 2. Since the guiding groove 13 is adapted to theguiding pin 11, the shank 6 can be displaced along the guiding groove13, but without the possibility of rotation. This is only enabled whenthe shank 6 has been pulled out fully forward, where the guiding groove13 opens out into an annular groove in the housing 2.

In this connection, “annular groove” is to be understood as also meaningdifferently shaped recesses of the housing 2 that permit a free rotationof the shank 6.

Apart from the shank 6, the crank handle 5 includes a crank arm 7, whichis connected to the shank 6 (or is produced in one piece with it) and atthe end of which there is an opening for receiving a grip 8. The grip 8is displaceable in the opening parallel to the shank 6 in the directionof an arrow 9 and can be transferred by the user from the pushed-inposition of rest according to FIG. 2 into a pulled-out working position,which is shown in FIGS. 3 and 4.

In the normal position or position of rest (cf. FIGS. 1 and 6), thecrank handle 5 can be accommodated such that it is lowered flush in arecess formed as a receiving pocket 14. The receiving pocket 14 belongsto a control panel insert 15 (cf. FIGS. 1 and 2), which is arranged atthe lower edge of the control panel 104 of the circuit-breaker 102. Whenthe crank handle 5 is pushed into its position of rest, an end face 12(cf. FIGS. 3 to 5) at the end of the shank 6 comes to bear against asupporting ring 34, which is loaded by a stop spring 33 (cf. FIG. 5).The stop spring 33 is a helical compression spring, which is fitted onthe drive shaft 3. Subsequently, the user pushes the grip 8 through theopening located in the crank arm 7 as far as the position flush with thecrank arm 7. The inner end of the grip 8 then bears against a stop 10.

In this pushed-in position of rest, the user in fact has no possible wayof gripping the crank arm, because the contour of the receiving pocket14 is adapted to the crank arm 7 with the shank 6 and the grip 8.Nevertheless, quick access is ensured if need be. This takes place bythe depth of the receiving pocket being dimensioned such that it islarger by a certain amount than is required to accommodate the parts.

The user can therefore press the crank arm 7 somewhat into the receivingpocket against the force of the stop spring 33. However, the grip 8cannot take part in this movement, because it is bearing against thefixed stop 10, and then protrudes by the same amount out of the crankarm 7. The user can then pull out the grip 8 and subsequently the crankarm 7 with the shank 6.

In a way similar to in the case of known travelling mechanisms, arrangedalongside the crank handle 5 is an indicating window 16, in which anindicating device 17 for the operating position of the circuit-breakerin its push-in frame can be seen. As known, these positions—operatingposition, test position and disconnecting position—relate to therelative position of movable main isolating contacts and auxiliaryisolating contacts, and, with a given arrangement of these isolatingcontacts, thereby to the position of the circuit-breaker 102 in theassociated push-in frame 101. On account of the engagement of thetravelling cranks 39 at the ends of the travelling shaft 37 in a fixedguide of the push-in frame 101, the angular position of the gear wheel 4consequently forms a reliable feature for the said positions.

According to FIGS. 3 and 4, for the purposes of the indicating device,arranged on an end face of the gear wheel 4 is a control cam 22, onwhich a sensing pin 21 of a two-armed indicating lever 18 bears underthe action of a tension spring 23 (FIG. 4). The indicating lever 18,which is pivotable about a bearing screw 20, consequently transfers thecontrol cam 22 into a position of the indicating means 17 that can beperceived by the user in the indicating window 16 (cf. FIG. 2).

In this case, it is important that, when actuating the crank handle 5,the user can easily see when the said positions are reached. For thispurpose, the control cam 22 is provided with portions of differentslopes, which are shaped in such a way that, shortly after leaving oneof the said positions, the indicating device in each case assume anintermediate position and indicate the following position only justbefore it is reached. The close proximity of the control cam 22 to thebearing screw 20 of the indicating lever 18 has the effect thatrelatively small deflections are transformed into movements of theindicating device 17 in the indicating window 16 that can be easilyseen.

The shank 6 is protected against being unintentionally pushed into thehousing 2 by a latched slide 28, which is loaded by a biasing spring 30(FIG. 3). The latched slide 28 is guided in the front part of thehousing 2 and likewise interacts with the end face 12 at the inner endof the shank 6. When the shank 6 is pulled out into its workingposition, the latched slide 28 snaps with one of its two edges facingthe drive shaft 3 behind the end face 12 and consequently blocks thepushing-in of the shank 6. In order to release the shank 6 forpushing-in, the user is provided with an actuating lug 31 (cf. FIG. 2),which is arranged in such a way that it protrudes into the receivingpocket 14 and is therefore only accessible when the crank handle 5 ispulled out.

The latched slide 28 has an additional function in the middle position(test position) of the travelling mechanism 1. As a difference from theoperating position and disconnecting position, this does not manifestitself to the user by a noticeable resistance at the crank handle due tothe reaching of end stops. In order that the user can nevertheless onlypush the crank handle 5 in when the test position is exactly reached,the latched slide 28 is provided with a tongue 29, which laterallyprotrudes from the housing 2 when the actuating lug 31 is operated and awindow opening arranged in the indicating lever 18 is opposite thetongue 29.

The travelling mechanisms of the known switches already have a devicewhich prevents actuation when the circuit-breaker is switched on (DE 4420 580 C1). For this purpose, access to the drive shaft is blocked by aprotective element. In the case of the travelling mechanism according toan embodiment of the invention, access to the crank handle 5 is alsodenied to the user in that, with the crank arm 7 lowered in the recess14, a first blocking mechanism that is activated for blocking theactuation of the drive shaft axially fixes the shank 6 of the crankhandle 5. This takes place by a first blocking element, formed as ablocking lever 24 (cf. FIGS. 2 and 6), in connection with a blockinggroove 26 (FIG. 2) arranged in the shank 6 of the crank handle andlimited in the axial direction of the switch. The blocking lever 24 isin this case analogously in connection with a first actuating element,formed as a blocking rod 27 (FIG. 2), as is described in DE 44 20 580C1.

If the preconditions for the travelling mechanism 1 to be actuatedsafely are satisfied, the blocking lever 24 is raised by the actuatingelement 27 in a way corresponding to an arrow shown in FIG. 1, ablocking lug 25 of the blocking lever 24 being pulled out from theblocking groove 26 of the shank 6. Conversely, switching on of thecircuit-breaker 102 is only possible when the crank handle 5 has beenpushed in again, into its position of rest in the recess 14, andconsequently the blocking lug 25 on the blocking lever 24 can enter theblocking groove 26 again.

According to FIG. 5, the travelling mechanism 1 of the novel switch hasa second blocking mechanism for blocking the actuation of the driveshaft 3. This second blocking mechanism serves the purpose of preventingtravelling of the switch in the push-in frame by means of a cylinderlock 41 (FIG. 5); 42 (FIG. 6) and/or when the door 42 (cf. FIG. 1) ofthe switchgear cell 100 is open. This second blocking mechanism alsofixes the shank 6 of the crank handle 5 in its axial direction 19 whenthe blocking mechanism is activated for blocking and when the crank arm7 of the crank handle is lowered in the recess 14. This takes place by asecond blocking element, which is formed as blocking pawl 44, inconnection with a second blocking groove 45, which is arranged in theshank 6 of the crank handle and is likewise limited in the axialdirection 19 of the shank 6. The blocking pawl 44 is formed as a punchedmetal part and is guided displaceably in the direction of the arrow 47perpendicularly in relation to the shank 6 on stop faces on thetravelling mechanism.

Apart from a blocking lug 48, which is formed on the side facing theshank 6, it has a window-like opening 49, from one inner wall of whichthere is formed a first holding pin 50 for a biasing spring 51, whichpin runs parallel to the direction of displacement 47 of the blockingpawl. A first arm 53 of a second actuating element 54, which is held onthe travelling mechanism displaceably in the direction of displacement47 of the blocking pawl, protrudes into the window-like opening 59 ofthe blocking pawl 44.

Serving for securing this second actuating element 54 on the travellingmechanism 1 is a cylindrical pin 55, which passes through inner walls,running perpendicularly in relation to the direction of displacement 47,of the actuating element 54 and fastening straps, opposite these walls,of the travelling mechanism. This occurs in the region of correspondingthrough-bores. For the axial fixing of the pushed-in pin, the pin has atapered portion 46, into which a resilient lug 56 of the fasteningelement 54 snaps. For dismantling the actuating element 54, this lug 36can be bent out by means of a screwdriver or a similarly narrow toolfrom the tapered portion 46 of the pin 55, and consequently the pin canbe released for pulling out.

Formed on the first arm of the second actuating element 54 is a secondholding pin 57 for the biasing spring 51. A second arm 58 of theactuating element 54 bears under the force of a restoring spring 59,which is supported on a first supporting face 61 of one of the housinghalves of the travelling mechanism, against a second supporting face 62of this housing half. For guiding the restoring spring 59, the onesupporting face 61 and the actuating element 54 are respectivelyprovided with a holding pin 63, 64.

Serving for controlling the actuating element 54 is a first,schematically represented cylinder lock 41. When this first cylinderlock 41 is closed, a lug (not represented) acts in the direction of thearrow 65 on the second arm 58 and displaces the actuating element 54 andthe blocking pawl 44, which is coupled to the actuating element 54 byway of the biasing spring 51, counter to the force of the restoringspring 59 out of an OFF position (cf. FIG. 5) into an ON position in thedirection of the shank 6 of the crank handle.

When the shank 6 is completely pushed in, i.e. with the crank arm 7lowered in its recess, the second blocking groove 45 of the shank 6 isopposite the blocking lug 48 of the blocking pawl 44, so that it canenter the blocking groove 45. When it is attempted to pull the crank arm7 out of the recess 14, the one side face of the blocking groove 45comes to bear against a stop face 66 of the blocking lug 48 andconsequently signals to the operating personnel that the travellingmechanism is blocked. A slight resistance is already sufficient here tosignal the blocking of the travelling mechanism.

As a difference from the first actuating element 27 of the firstblocking mechanism, the second actuating element 54 can also bedisplaced out of its OFF position into its ON position when the crankarm 7 is not lowered or not yet completely lowered in the recess 14.With the shank 6 pulled out completely, when the actuating element 54 israised the blocking pawl is likewise raised and consequently protrudesinto the path of movement of the shank 6. When the shank is pushed in,the end face 12 of the shank 6 slides over a sliding surface 67 of theblocking lug 48 of the blocking pawl and presses the blocking pawl 44counter to the force of the biasing spring 51 out of the path ofmovement of the shank. After that, the blocking lug 48 slides along on aflattened casing portion 68 of the shank until it engages in theblocking groove 45.

For alternative actuation of the blocking pawl 44, the second actuatingelement is coupled to a third actuating element, formed as a two-armedlever 70. For the coupling attachment, the second actuating element 54has at the free end of its first arm 53 a U-shaped recess 71, into whicha first arm 72 of the two-armed lever 70 engages. This two-armed levercan be pivoted about a fixed bearing screw (not represented), whichpasses through a bore 74 of the lever 70. The second lever arm 75 of thelever 70 can be actuated by way of a pawl 73 of the cylinder lock 42(cf. FIG. 6) in the direction of the arrow 77.

According to FIG. 6, serving for controlling the movement of theactuating element 54, and consequently for controlling the secondlocking mechanism, is a device which has a push element 80 provided withan oblique surface 81. This push element 80 is formed as a punched/bentmetal part and has in addition to the oblique surface 81, which isinclined at right angles to the direction of the travelling path of theswitch, an angled-away supporting arm 79 for bearing against the innerside 84 of the door 42 of the switchgear cell 100 (cf. FIG. 1) and awindow-like opening 85, for receiving a restoring spring 86, and a bore87, forming the abutment for one end of the restoring spring.

The angled-away end 83 of the supporting arm is curved in such a waythat it bears against the inner side of the door at a point, andconsequently with low friction. The window-like opening 85 extends inthe operating direction 91 of the restoring spring and therebyapproximately at an angle α of 45° obliquely in relation to thetravelling direction 82 of the switch. The angle α between thetravelling direction of the switch and the operating direction of therestoring spring should preferably be between 30 and 60 degrees.

The abutment of the other end of the restoring spring 86 is formed by abore 88 in the push-in frame of the switch. Also formed in the push-inframe, parallel to the operating direction 91 of the restoring spring86, are three guiding slots, forming a three-point bearing for the pushelement, of which only one 89 can be seen in FIG. 6 and which arerespectively passed through by a guiding pin riveted onto the pushelement, the free ends of the guiding pins being provided with a collar,the diameter of which is made wider than the width of the guiding slots.One end of the guiding slots is respectively widened in such a way thatthe pins with their collar can easily be inserted into the slots. Theother end of the slots respectively forms a stop 90, on which the pushelement is held under the force of the restoring spring when the door isopen.

In this stop position of the push element, a working surface 93 whichadjoins the upper end of the oblique surface is opposite a rounded-offfree end 92 of the second actuating element 54, whereby the secondactuating element 54 is activated in its ON position, and consequentlythe second blocking mechanism in its blocking position. When the door isclosed, the inner side 84 of the door 42 comes to bear against theangled-away end 83 of the supporting arm 79 of the push element anddisplaces the push element 80 counter to the force of the restoringspring 86 obliquely in relation to the travelling direction 82 of theswitch in such a way that the oblique surface 81 of the push elementslides laterally on the free end of the second actuating element untilthe lower end of the oblique surface is opposite the free end (cf. FIG.6). As a result, the second actuating element is released and, under theforce of the restoring spring 59, assumes its OFF position, whereby thesecond blocking mechanism is transferred into its release position.

As an alternative to this embodiment of the device, the oblique surfacemay also be formed on the push-in frame of the switch, the push elementthen acting on the second actuating element as it slides on the obliquesurface.

Exemplary embodiments being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the present invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

1. A device for controlling a blocking mechanism of an electric switch,in such a way that it can travel in a switchgear cell, comprising: apush element; and an oblique surface, the oblique surface extending inthe direction of the travelling path of the switch when the device is inan installed position, wherein the push element is displaceably held inthe switchgear cell in dependence on the position of a door of theswitchgear cell, wherein the push element co-operates with the obliquesurface, acting on the blocking mechanism in such a way that theblocking mechanism is in a release position when the door is closed andin a blocking position when the door is open, wherein the obliquesurface is inclined transversely in relation to the direction of thetravelling path of the switch and wherein the path of movement of thepush element extends obliquely in relation to the direction of thetravelling path.
 2. The device as claimed in claim 1, wherein theoblique surface is formed on the push element.
 3. A switchgear cell,comprising: an electric switch, arranged in such a way that it cantravel in the switchgear cell; a travelling mechanism; and a blockingmechanism for blocking the travelling mechanism, wherein the blockingmechanism is controlled via a device as claimed in claim
 1. 4. Aswitchgear cell, comprising: an electric switch, arranged in such a waythat it can travel in the switchgear cell; a travelling mechanism; and ablocking mechanism for blocking the travelling mechanism, wherein theblocking mechanism is controlled via a device as claimed in claim
 2. 5.A switchgear cell, comprising: an electric switch, arranged to travel inthe switchgear cell; a travelling mechanism; a blocking mechanism forblocking the travelling mechanism; and a device for controlling theblocking mechanism, the device including, a push element, and an obliquesurface, the oblique surface extending in the direction of thetravelling path of the switch when the device is in an installedposition, wherein the push element acts to release the blockingmechanism when a door of the switchgear cell is closed and to engage theblocking mechanism in a blocking position when the door is open, whereinthe oblique surface is inclined transversely in relation to thedirection of the travelling path of the switch and wherein the path ofmovement of the push element extends obliquely in relation to thedirection of the travelling path.
 6. The switchgear cell as claimed inclaim 5, wherein the oblique surface of the device is formed on the pushelement.